The electronic payment is a method that has gained popularity throughout time. There are numerous well known systems that allow making this kind of payment.
At first, these systems were based completely on the traditional cable telephone communications and on magnetic band card readers placed in shops. But with the arrival of Internet and the mobile telephony, new methods of virtual payment have appeared. Specifically, there is a well known payment system by mobile telephone that is based in the association of a credit/debit card number with a PIN and a mobile telephone number in the transactions server. The procedure followed by the system is, basically, the authorisation of the operation by the user, once the transaction data is received in his mobile phone. The transaction is not completed until the user confirms it with his mobile phone, entering his secret PIN. The communication with the user, in order to authorise such transaction, is done via a data call from the transactions server, which will take control of the introduction of data with the keypad and the representation of the information on the telephone screen. When buying at the merchant's site, a specially configured POS is required, in order to pay with this system, because the transaction must start with a special call to a telephone number, call that is handled by the transactions server.
This system suffers from rigidity, due to the fact that the communication with the user is done via a data call, which makes it difficult for the system to be worldwide spread, and therefore it will be necessary to have transaction servers in each country. On the other hand, due to the fact that the system needs to take control of the mobile handset, and this control depends on the different mobile phone brands and models, and since that control is not standardised, it will be necessary to have different modules for each different mobile phone, and also for each new model, which will make it even less universal. Moreover, the user will be forced to learn new instructions every time he uses a different model. A connection via the WAP protocol, which allows a greater standardisation, would make the process a lot more expensive for the user, due to the large quantity of data required in the connections using this method. On the other hand, the limited keypad of the mobile phone affects the introduction of the required alphanumeric data, in a WAP connection, what makes the transaction process slower, in case of using the mobile handset as a phone for purchasing/selling. Finally, the own conception of the system requires the presence and use of POS terminals in the shops.